Aesthetic: It is something artistic or beautiful or tasteful.
Ascetic: The one who abstains himself from pleasures and luxuries mostly for religious purposes.
Usage of Aesthetic:
1) The lady was praised for her aesthetic sense.
2) The furniture is both aesthetic and functional.
Usage of Ascetic:
1) He wanted to lead a life of an ascetic after retirement.
2) Is a perfect ascetic life practical in the present world?